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Discussion Starter #1 (Edited)
1973 Saab Sonett Conversion w/Nissan Leaf Drive System

Status Update 1/12/16:
- Obtained a running/driving salvage 2012 Nissan Leaf
- Completed Leaf teardown, demonstrated system functioning outside the Leaf
http://www.diyelectriccar.com/forums/showthread.php/re-using-complete-leaf-drive-system-151458.html
- Removed outdated 96V DC PbA based system from Sonett
- Sonett teardown to frame nearly complete

Plans:
- Make more accurate measurements of Sonett frame, and Leaf components to finalize placement and fabricate necessary mounts and brackets.
- Initial focus will be to make bare Sonett chassis drivable / functional for continued testing of Leaf Drive System re-use.
- Phase I will likely be similar to Leaf tabletop demo, retaining Sonett brakes, hubs, and steering with modified drive shafts to adapt Leaf transaxle to Sonett hubs. Components from Leaf to include Motor, Inverter, VCM, BCM, DCJB, On-Board Charger and Charge ports, Shift Control, Power On Control, wiring harnesses (inc 12V fuses, relays), liquid cooling system, some display and control instrument / switches.
- Phase II will likely aim to fully enable regenerative braking, may incorporate Leaf braking system (master cylinder, brake controller, ABS controller, calipers, parking brake controller), hubs and wheel speed sensors (preferably in modified Sonett knuckles to avoid suspension changes), possibly adapt steering sensors and electric power steering.
- HVAC and other creature comforts (audio, door locks, Nav, Telemetrics, electric heater) will probably be incorporated throughout phase I and II as practical / convenient.
- Final phase will be to work on restoration / cosmetics once function and fitting of components are complete.

Original Post:
Well, after about 10 years of EV dreaming, I finally took the plunge :)

I've always had a soft spot for these odd-ball Saab's, ever since owning one (that I could barely keep on the road) back in the late 90s. When researching platforms for a conversion, I was rather pleased to discover that they seemed to be an excellent candidate. With a curb weight of 1800 lbs, a Cd of 0.31, and a miniscule cross sectional area (22% smaller than 1st Gen Insight), they were fun to drive with the stock ~60 hp engine while averaging 30-35mpg in a day when 10-15mpg was typical. They were also designed as racers, being proven as a great platform for performance enhancements and doing quite well in their SCCA and rally classes.

I wasn't planning to start my search in earnest for another month or two, but when this example came up for sale locally, I couldn't say no ;)
It was about the same price that I would have spent on a fair condition runner in need of complete restoration, but had already had a simple DC conversion done in the 90s and a significant amount of work had gone into restoring the frame/floorpans and mechanicals as it passed through the ownership of two different vintage Saab restoration gurus. If nothing else its a great rolling chassis to build on, with a bonus that the old conversion has been maintained and rebuilt well enough to still be used as a commuter in the mean time.

The conversion is definitely a bit of a time capsule from a bygone era ;) From what I gather it was based on a kit from either EV America and/or Solar Car Corp in FL with a custom adapter / coupler designed by Saab Quantum designer Walter Kern to the original 4sp freewheeling transmission (used clutchless). It uses a 6" GE Series Wound DC motor (looks to be the 11.6HP commutavan motor) with forced air cooling, a Curtis 1221B-7401 controller set for 300A max, and a 96V flooded lead acid pack. Looks like it was originally set up for 16s 6V batteries, but changed over to 8s 12V at some point. Have to start in 1st gear to get it rolling, then 2nd will do just about everything except freeway speeds. Haven't tried that yet ;)

It seems like its gone through several incarnations, mostly reusing the original components. Original conversion was done '92-93 by Bud Clark of J&B Imports in CA following Walter Kern's design. System was removed and significant restoration of floorpans and mechanicals was done in 2009-10 by Jack Ashcraft in OR. Motor and Controller were rebuilt by subsequent owner in 2013, and funky split 55V chargers were replaced with a Delta-Q unit in 2014. 5/8 batteries are Trojan T1275s from 2014, 3/8 are US 12VXCs from 2009 that are getting pretty weak. Still good enough to drive it 13 miles home on surface streets and come to rest at 12.2-12.3V though (vs. ~12.6 on the Trojans).

I'm planning to get those last 3 old batteries out of there, and add some instrumentation (probably cycle analyst and a modified Celllog 8S) and keep using it for my daily 15 mile RT commute while starting plans for a major update :)

 

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Discussion Starter #2

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Discussion Starter #4 (Edited)
I'm intrigued by the idea of trying to use the complete drive system out of a wrecked leaf, so that's been my primary area of research so far. I know that some folks have been trying to use individual components, but not sure anyone has tried using the whole system together (VCM, motor, inverter, charger, cooling system, maybe brake control unit, maybe some creature comforts like keyless entry and AC). I'll plan to start another thread on that topic unless someone can point me to a good one already under way :)

My motivation for exploring this route is mainly a robust, integrated drive system with decent acceleration and range performance on a budget. Although it will certainly have its own challenges, $5-7k for a wrecked Leaf that yields an 80kW 3 phase motor w/reducer and transaxle, water cooled inverter, 24kWh Li battery with bms, charger, etc seems pretty untouchable performance per $ wise. Even with some probable battery degredation, I would imagine I'd be able to cover my typical 20 mile RT commute with plenty of room to spare.

I've done some preliminary rough CAD modeling to check feasibility, and so far it seems like everything would fit. Here's a drawing of the Sonett's frame with approximate represenations of the motor/reducer/transaxle, inverter, batteries, and radiator.


I've also done some work in the "Excel Dyno" to get a sense of what kind of performance might be possible when moving the Leaf's drive system from its original 3600 lb host into an 1800 lb platform. The values to the far right are the baseline Leaf performance, which seem pretty reasonable, while the third column from the right estimates acceleration characteristics in the Sonett. The assumes you can keep all that torque applied to the road (which the spreadsheet says you can't), and uses motor torque data measured directly at the wheels of a Leaf on a dyno.



Could be fun ;)

Rob
 

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I'm very interested in doing this as well just trying to figure out what car I want to try to use and LOVE convertibles! I'm actually thinking an 1985 Volkswagen cabriolet or a 1974 fiat 124. I'm not certain the drivetrain would fit in the Fiat though. Would need to know the demensions on both from afar :/
Good luck on the project!!!
 

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May I ask where you bought that and price? What else are you getting out of that besides the engine(traction motor, inverter, charger); battery, and ECM?
 

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Discussion Starter #8 (Edited)
2012, 24k miles from WA State using autobidmaster/copart. Supposedly "run&drive verified", we'll see ;)

Winning bid was $5300, on no reserve / pure sale. With fees and shipping to Phoenix ends up being just under $7k.

At the high end of my budget, but as I'm planning to use quite a lot of stuff from the car it seemed to make sense to pass on the ones with more substantial damage and hold out for one that seemed pretty intact. I'm not sure if this one hit at a funny angle or what, but it _looks_ like there is damage to quite a few panels but not much deformation structurally into the engine bay. We'll see what the real story is when it gets here. I had been mostly watching side/rear impact ones, but most of the ones I had seen in the last month or so ended up going for over $7k plus shipping and fees, for 2011s with more miles.

My general plan is to use enough of the Leaf drive system to get it to operate as if its in a Leaf. So far it looks like:

Pretty much for sure: battery w/LBC & contactors, motor, inverter, charger, VCM, BCM, power switch/NATS amp, key, security dongle, charger, electronic shifter, radiator, water pumps, drive shafts (cut down), IPDM, DC/DC Converter

Maybe: Intel Brake Unit (looks necessary to enable regen), AC system (in Phoenix), wheel hubs/knuckles/brake calipers and wheels (still debating), displays and AV-CAN (maybe temporarily, then replace with custom control interface / displays?), brake/throttle pedals and/or sensors, steering sensors and or rack (if needed to get regen working)

BTW I have another thread going in the tech discussion section where I've been tracking my efforts to use the DTC failsafe tables in the factory service manuals to sort out the minimum required set of components to enable full drive / charge functionality.
http://www.diyelectriccar.com/forums/showthread.php/re-using-complete-leaf-drive-system-151458.html

Rob
 

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Discussion Starter #9
Looks like I got lucky! Leaf arrived today, had low battery warning and 6 miles range remaining, but started right up and drove off the truck. Small number of minor DTCs, after clearing with LeafSpy no DTCs reappeared. All fluids seem to be holding level (coolant, etc), AC works fine. Printed a temp permit and drove (very slowly) to Nissan dealer 3 miles away, still showing 6 miles range. Tried level 2 charging, started right up at 3kW. Switched to QC, charged to 80% (49-188 GIDs) in about 40 min at 17-18kW. Battery showing 11/12 capacity bars. Drove to work with AC (~10 miles, 92F) with no issues, glides well, brakes straight, no wheel pull or vibrations. Still no DTCs after drive, ~60 mile range still showing and average >5m/kWh for the trip. Pretty jazzed!

Its almost going to be sad to cut this one up. Almost ;)

Rob
 

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Excellent project! Question, do you have a dealer license, did you bid on one of the 'open to public' copart auctions, or did you hire a broker?
 

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Discussion Starter #12
I ended up using a broker, autobidmaster.com. I was quite happy with the whole experience. They charge a ~$300 broker fee, but then you can search co-part inventory, setup watch lists, save searches, email notifications, make advanced bids, and best of all make real time bids in the live copart auctions. Their live auction interface looks just like coparts, so it seems like a direct feed. That was the main reason I chose to go with them, as bidding live seemed most likely to produce a good result. Phone support was very helpful when I had questions, and they arranged shipping at what seemed like a good price ($785 WA to AZ).

It looks like I may have gotten lucky, but you do have to go into these auctions with open eyes. There are a lot of fees that add on top of your final bid. There are essentially no guarantees what-so-ever on the condition of the car. You get 10 photos, and have to roll the dice and take your best shot. You can pay someone to go inspect it, but they won't allow a code scanner and unless you go pick it up yourself in person you don't even really have any recourse if it arrives significantly different than described / depicted or as it was when inspected. Even a "run and drive" verified car only means that when it arrived on the lot it would start (sometimes with a jump) go into gear and move a few feet under its own power. Then the car will often sit on the lot for at least a few months (while insurance companies and state governments shuffle papers back and forth), during which time its condition can degrade. That said, mine was "run and drive verified" and arrived with the 12V battery still good and the HV battery still showing exactly the same remaining range as when the pictures were taken.

Its also not unusual for easily resellable parts/accessories to walk off somewhere in the process. Charge cords are probably the most likely to be missing on a Leaf, either the original owner keeps it to sell, or it disappears so where along the way. I've heard of a few cases of the NAV sim cards going missing, which is a real pain if you plan to use or resell. In extreme cases I've even heard of more substantial things like hybrid batteries going missing. Keys can end up lost, even if they were originally present, which is also a pain.

Even taking all these risks and extra costs into account, it can still be a really good deal. But you have to be realistic about what you are getting into.

Rob
 

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Wow, thank you so much for sharing your first hand account. I have been eying copart auctions (Leafs mostly) for a while, but I just had too many unanswered questions. Your input is greatly appreciated! Congratulations on your win, it looks like you got a good parts mule:)
 

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Rob,
Not sure if the Leaf Drive train fits under the hood of Sonett.. Please measure before ripping the Leaf..

Looks like I got lucky! Leaf arrived today, had low battery warning and 6 miles range remaining, but started right up and drove off the truck. Small number of minor DTCs, after clearing with LeafSpy no DTCs reappeared. All fluids seem to be holding level (coolant, etc), AC works fine. Printed a temp permit and drove (very slowly) to Nissan dealer 3 miles away, still showing 6 miles range. Tried level 2 charging, started right up at 3kW. Switched to QC, charged to 80% (49-188 GIDs) in about 40 min at 17-18kW. Battery showing 11/12 capacity bars. Drove to work with AC (~10 miles, 92F) with no issues, glides well, brakes straight, no wheel pull or vibrations. Still no DTCs after drive, ~60 mile range still showing and average >5m/kWh for the trip. Pretty jazzed!

Its almost going to be sad to cut this one up. Almost ;)

Rob
 

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Discussion Starter #15 (Edited)
Yeah, I was worried about that too. That was a big part of the decision to go with the 2011-12 vs. 2013+. The stacked motor / inverter / charger might have just fit, but it would have been very tight. The separate components of the earlier design should make it much more flexible. There is a crude CAD mockup on the first page showing the approximate motor/reduction gear/transaxle, inverter, and battery modules in relation to the front and rear compartments. Looks like it should all go in ok, but I will be refining measurements now that I have both cars. Need to start adding secondary components and look at weight distribution as well.

Since this one seems quite drivable, my plan is to start by doing some experimenting on the system while its still in the Leaf to make sure I understand how it will react to the absence of various components. Hopefully that will line up well with what I've gleaned from the service manuals, but if not I want to know about it before I take it all apart and try to re-assemble in the donor :)
 

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Discussion Starter #16
Not sure where you are located electron_bom, but if you start looking to buy I would also make sure to have a pretty wide search area. I started with a focus on CA, with a mind to keep shipping costs down, but the auctions there seemed very popular (often 1000 or more participants noted on the live auction) and prices seemed high. The auction I won this one at was in WA and only had a few hundred participants, and while shipping was probably $300-500 higher I'd guess the winning bid ($5,300) was easily $2-3k less than a similar car in CA.

Rob
 

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Discussion Starter #17
Managed to track down a "parts kit" for the 24 module pack from someone that was breaking down batteries for the modules. Plan is to use these to combine the modules from the smaller packs so that I end with two identical 24 module 1/2 packs. May still be some wiring challenges to sort out, but I will likely have to be making some custom harnesses anyway.



Rob
 

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Thanks for the tips regarding autobidmaster, I'm currently shopping for a busted leaf of my own. I'm on the east coast and the $1700 shipping quote from the Cali auction site has me searching closer to home.

Have you removed the battery enclosure from the vehicle yet? I'm wondering what is entailed in its removal. I'm assuming it will drop out from underneath the vehicle.

Given your last pic, am I correct in understanding that you will utilize the OEM bus bars to connect the cells in series, but you're manufacturing your own BMS leads?


Post more pics please! :)
 

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Discussion Starter #19
Thanks for the tips regarding autobidmaster, I'm currently shopping for a busted leaf of my own. I'm on the east coast and the $1700 shipping quote from the Cali auction site has me searching closer to home.
On the east coast you might try looking at the GA auctions. Seems like the state incentives there resulted in a lot of Leafs on the road, which of course means more wrecks.

Have you removed the battery enclosure from the vehicle yet? I'm wondering what is entailed in its removal. I'm assuming it will drop out from underneath the vehicle.

Given your last pic, am I correct in understanding that you will utilize the OEM bus bars to connect the cells in series, but you're manufacturing your own BMS leads?


As you've probably seen, the Leaf battery is divided into a number of sub-packs. The big one across the back is half of the battery, 24 modules. Its this pack that I found extra parts for, so my plan is to disassemble the smaller packs, which will yield 24 more modules, and then connect them back together with the stock bus bars to yield a second 24 module pack. So the goal is to keep the battery looking like stock to the drive system, but have just 2 identical 24 module packs to deal with which should be simpler to integrate into the host vehicle.

The parts kit came with a spare 24 module pack BMS harness, and I'll also have the harness from the smaller packs from my own battery. The connectors appear to be the same between the large pack, and the combined smaller packs, but the pin order/locations look to be different. Hopefully I'll either be able to make the "small pack" harness out of my battery work with the newly assembled larger pack, or re-pin the 24 module harness from the parts kit to match the smaller pack pin out. Either way this will take some careful work to get right to avoid damaging the bms ;)

Post more pics please! :)
Here is where I'm at currently:


It will be a while until I drop the battery. My plan is to strip down the interior, dash, and front body so that all of the major components are accessible but the car can still be driven. Then I can use this as a platform to test all of the mods required for the transplant before the system is completely disassembled. Some will just be as simple as unplugging various controllers to make sure my assumptions about what components can be omitted are correct, but I'll also plan to remove the battery, rewire the pack and then temporarily install it back into the the leaf interior to test that all out.

I've started by exposing the rear area as I'm also interested in the possibility of upgrading the battery charger, either to dual stock chargers or perhaps a 6.6kW unit out of the 2013+ models. I've found a potential local source for parts (as well as picked up a busted 2013 charger from a scrap yard for $75) to start experimenting with, though to really go down that path I'll have to pick up a CAN controller and start looking at all that in a lot more detail. Not sure how far down that path I really want to go yet, as my normal commute will only use a fraction of the battery capacity, but having a faster charge option would be nice and might be useful to the 2011/2012 Leaf owners out there if I can make it work.

Rob

 

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